Hydraulic scale



Feb. 8, 1944.

R. s. BOHANNAN HYDRAULIC SCALE Original Filed Aug. 3,-1938 2Sheets-Sheet 1 Robe/'7 5. Babe/man INVENTOR ATTORN EYS Patented Feb. 8,1944 2,341,174 HY RAULIC "SCALE Robert 'S.'Bohai1'ritn, Toledo, "Ohio,assiznar ul) Toledo Scale Company, Toledo, Ohio, a corporation ofNewfler'sey continuation or application SapietlNo. 1222 331, August 3,1938. This application December 19, 1941, Serial No. 423,592

9 Claims. l. 265-47) mechanism willexert a like 151.111 on the scalebeam. I v

It is one object of my invention to transmit to the scale beam the sumof the fo'ioe, applied by the load at the same time to the severe-1'hydraulic fluid o'olumhs, through separate 1everage transmissions to acommdn mechanioe'l compensator, provision being n ia'de' through theadjustment of "each transmission to cause el l equal pull to bee'xitd'on the bea z'nby a given load in different'oiresbofiding positions onthe stale platform.

My invention f ifthef-ontemplates the ates the com ensator; oneadjustment being means of knife edge bearings that are sli'dable' alonga. pairof parallel spaced cooperating levers, and. the other b'eiiigbyii'iearis of a-screw con? trolled shifting o'f'a'k'r'iifeedge bearingforming the fulc'rum for one of the levers of each'ioti'r of'cooperating leti'ers',

My inventiofi tufthf 'c ompiisesthe use of a compensator in the'form'ofa: rocker bar carry-1 iiig a lever of each leverage transmission and thelever for a'Cfiliatihg the beam.

My invention further o'dmpjis's novel fa'j tines in the design *dfth'ecomponent leve'r's of e'ach 1everage transmission, and also in thedesign of check rods used to hold the lVeTs"l1eLv-' mg adjustable"fincr'ums "against dis lacement.

illiistralted in the a'c'cdiiip' lnying drawings, in which:

.Fig. I is a fragrfiefittry pi'an View or 9; settle withits'plat'foifrfi roken away and we of its diaphragm exposed at un en'd.

Tr -'1 soetle illustratd iii Fig. I.

t in awe-on ofthe cm s'iet i and 25 to distinguish'jth m 55 Fig. 1111sa; tra 'sver e li ks-sectional vi'et'v taken on the line III-III, Fig.I. H v

Fi ,IV is ec a yertica cross- View through-one o; the tilatform d iaphgms l I-Ti -v V i h. r dg i fiwUn showing t e "knife edge tearingat'b'lie'en'd of e l vr Fig. V1 is an enlarged viewinside jeltftioh of hme an sm. n. thecqmn n ett xq eb i e shown under the beam on thescales't'ahd in' Fi'g. got, r "Fig; V1115 oros'sfsedioiialwiew wk-@11 9"thg i IIl-WlIP F .1 ,;w' h i m. o. 1. p zti titi'or broken away and cttih ,of,jt 'e levers p f n blah! nd partl b En 'y- Si i1 r reference'riu'metels "refer to "sir'ioiifii' fiarts tlirbughoutth drtwitigs.

a truck scale, It wi ll v be iinjdei'sftood the scale pla m 11.0. may.ben x n s z an, h fi according to the partiouler iiu tjy rquireq 'f thescale, and it may be adiptedtore'o e trpeks,

silita 'bl'e manner through 'thjiit 12 to al point where they can passup and enter the compensator cabinet 26. As shown in Fig. VII the end ofeach of these ducts in the cabinet is screwed into a separate threadedport leading through the side wall 28 into the horizontal partition 21forming parts of a metal frame mounted within the cabinet and boltedoverhead to the transverse frame member 29 of the beam stand. Thispartition 21 is enlarged to form each of the ports 30, the bore of whichextends only partly therethrough with its inner end intersected by avertical bore 3| leading through the partition and having threads tappedin its upper and lower ends. The upper end of each bore 3| is closed bya nipple 32 through which the system is filled with hydraulic fluid andwhich is in turn closed by a screw cap 33. The lower end of each bore 3|has a screw connection opening through the upper head of a bellows 34.The lower head closing each bellows is made fast to a seat 35 by a screwstud 36 which passes through its respective lever 31 and seat 35 andsecures the bellows thereto.

Where four platform diaphragms are employed there will be four of thehydraulic fluid columns, four of the bellows 34 and four of thesetransmitting levers 31. All of these corresponding parts will be similarand thus can be stocked in duplicate.

Each transmitting lever 31 has at one end an upturned portion 38 and ahorizontal bearing end 39 parallel with the transmitting end 31 of thelever. A slide bearing block 40 is adjustably connected by means of aset screw 4| with the bearing end 39 of each of said transmitting 1eversand it has seated fast in its under-face, in a plane normal to thelever, a knife edge bearing block 42. This bearing is engaged in agroovedseat provided in a lower bearing block 43 which is supported on asub-platform 44 under, and in spaced relationship to, the partition 21.The upper surface of this sub-platform 44 is horizontal and it extendsthe full width of the metal frame in the compensator. An end plate 45 issuitably attached to the free edge of this platform and rises above itand is bored to receive the reduced inner ends of four adjusting screws46 which are screwed in the end of the cast frame and project beyondsame, and if desired outside of the cabinet so as to be readilyaccessible for adjustments.

Each transmitting lever 31 is connected by a check rod 41 to a shoulder48 below the sub-platform by means of screws engaged in said shoulderand in the adjacent end of the lever 31, these rods 41 having the holesfor the screws larger in diameter than the shanks of the screws andmachined to provide a knife edge as seen in Fig. V, so that they willnot, by binding against their respective screws, check or restrain thefree vertical play of their respective levers 31. A nose iron 50 isfitted slideably over the free end of each lever 31 and is adapted to beset in any desired adjustment thereon by its respective set screw Theupper end of the nose iron is fitted between the side members 52 of aloop 53, the upper end of which is engaged over a C-link 54 whichoverhead is connected by duplicate elements 50, 5|, 52 and 53 to arocker arm 55, each substantially parallel with its respective lever 31.Each of the nose irons of a link connection has a knife edge bearingblock 56 or 51 engaging its respective loop 53, these bearings beingrelatively inverted as shown in Fig. VI.

All four of the rocker arms 55 are rigidly connected to a horizontalrocker bar 58 having end bearing points 59 which center it and supportit practically free of friction in seats formed at inner ends of screwbearings 60 which are carried by brackets 6| bolted to the top 62 of themetal frame in the compensator cabinet 26. These four rocker arms 55 areequally spaced along and rise from the upper portion of the rocker bar58. In its center, and connected in under-hung relation thereto, is anelongated pull lever 63 which is disposed parallel with the rocker arms55 and projects into position to receive a nose iron 64 connected byknife edge bearing block 65 to the arms of loop 66 which is engaged overthe hook 61 on the pull bar 68 leading up, and connected by an upperhook 69, to the loop by which the pull is applied to the scale beam orother load counterbalancing mechanism generally designated by thenumeral 10. This beam carries the usual sliding weights, counterweightsand the adjusting weights, all of which being of standard design andconstruction need not be specifically designated herein. The pull bar 68passes through an opening 1| leading through the top frame member 62 inthe compensator cabinet and through the transverse member 29 of the beamstand, the hole being large enough to permit a certain amount ofadjustment to the nose iron 64 on the pull lever 63, which is adapted tobe set in adjusted position by a set screw.

The scale and beam stand elements having all been assembled and thejoints made tight connecting the fluid ducts to the diaphragms and tothe compensator ports with which they are respectively connected, theoperation of the scale may be thus described:

The load on the platform will depress all of the platform diaphragms butforce will not be applied to all the diaphragms in an equal degreeunless the load be centered on the scale platform. The force applied bythe load, whatever its position on the platform, to the several platformdiaphragms will be separately transmitted from each diaphragm to itsrespective bellows 34 and each bellows will be expanded in directproportion to the force applied to the fluid column controlling it. Theexpansion of the several bellows will be away from their upper seatswhere they are connected to the partition 21, and thus each will forcedownwardly its respective actuating lever 31. Such lever will rock onits fulcrum knife edge bearing 42, 43 and its free end, through theconnection described, will impart a pull downward to its respectivelever 55 on the common rocker bar 58. A downward movement of such lever55 is resisted by the upward pull from the rod 68 exerted by the balanceweights of the scale beam. Therefore, the rocking motion imparted to therocker bar 58 by the combined thrust from the four bellows 34 throughtheir respective actuating levers 31 will be transmitted through thepull lever 63 of the rocker bar to the pull rod 68 that operates thescale beam.

The equalization of the transmission pull from different parts of theplatform is attained by placing a standard weight in correspondingposition in each corner of the scale platform and adjusting theconnections in the compensator cabinet 26 so that for each position ofthe weight, the scale beam will read alike.

The original rough adjustment to seal out each corner of the scale ismade by loosening the set screws 5| and by bodily shifting the linkagebetween the individual lever 31 and the respective arm 55 f thecommonrrocker bar 58. When the linkage has beensoishifted that theweighing scale mechanism reacts approximately correctly to the amount ofloadon the corner in question, theset screws 51 are tightened inplace.Care must be taken when shifting such linkage that the bellows lever .31is maintained in such a position that the screws extending through thecheck ,rod 4.! are approximately at the-center-of the apertures throughwhich they extend. The

set screw 4.! may also be loosened and the block 40 shiftedon'theend:39-01 the lever 31 to;.properl y position the lever with respect to therod 41.

When the set screws 5| and set screw ll-are tightened, this tighteningmay shift, slightly the connections between the respective members andthe lever armson which they are secured by It also may be thatthe rough.

the set screws. adjustment made by shifting theseqmembers is notaccurate enough correctly to adjust the corner.

Fine adjustments, in order to fseal out each individual corner, are madeby turning the screw 46 which slides the block43and varies the conditionof plumbness of the linkage connecting the lever.3 l to the respectivearm-55 of the rocker bar 58. It is, of course, impossible todetect bythe eye whether the linkage is truly plumb, and

the load counterbalancing mechanismof lthe sca-le.

varies the force which is applied through the.

linkage since the force applied thereby is different, depending uponwhether the linkage is,

truly vertical or tilted to one side or the other.

It will be noted that in each transmission the cooperating lever 31 androcker arm 55 occupy positions of substantial parallelism at all timesand have their pivotal mountings at opposite ends. Thisis necessary toobtain the requisite "adjustment of the leverage Ii-n'the transmissionsso that each may be caused to exert the exact eifect desired on thescale beam. Thus, as the nose irons 55 of :each transmission are shiftedtogether to the right. minishes and the same is trueof the force exertedthrough the corresponding lever 55, thus there will be a dimunition ofthe force transmitted bya bellows to the pull lever 63'. When the noseirons are shifted to the left, the reverse is true. In like manner, asthe fine adjustments are obtained by the shift of the fulcrum point foreach lever 37, the force exerted through its respective nose irons ismodified and by their exact adjustment throughout the severaltransmissions the correct force to be transmitted to the beam isobtained.

Obviously the forces exerted by the independent bellows 34 through theirrespective levers 3'! and transmissions to the pull lever 63 willrepresent the sum of the force applied by the load to such bellows.

The scale beam, as herein referred to, is used as a comprehensive termrepresenting any movable weight or value indicator such as a beam, dialor pointer, and in like manner the term platform as used is inclusive ofany means to receive or support the load to be weighed, and the termdiaphragm is inclusive of either the type Fig. VI, the force exerted bylever 31 (ii-'- aotuates .the leverage transmission.

- While .I have shown my invention in but one form, is will be obviousto those skilled in the art that fit is not so limited, but issusceptibleto various changes and modifications, without departing fromthe spirit thereof.

What I claim is:

1. -In a hydraulic scale, a scale platform, supporting diaphragmstherefor, a scale indicator, a rocker bar actuator for the indicator, aplurality of 'leverage'transmissions each including .a lever,

which jointly operate sai'd'rocker bar actuator, a-

bellows-operatively connected tothe corresponding lever of eachtransmission and adapted to operate same,;a. fluid duct connecting eachplatform diaphragm with a corresponding bellows, means to fill each:duct and that one of said diaphragm and :said bellows connected therebywith a confined liquid body, means to vary the-cooperative relation ofthe lever in :each

transmission to vary the :effect of "a given-expansion :of :itsrespective :bellows on said rocker bar actuator, :and screw means toadjust the fulcrum for the. lever .in each transmission.

32.11119, hydraulic scale, a scale platform, supporting diaphra'gmstherefor, a scale indicator, av rocker bar actuator for the indicator, aplurality of leverage transmissions each including a lever, whichjointly operate said rocker bar actuator, a bellows operativelyconnected to the corresponding lever of each transm-ission and adapted ioperate same, a fluidduct connecting each platform diaphragm with acorresponding bellows, means to tfill each duct and that one of said.diaphragms and said bellows connectedthereby with .a confined liquidbody, means to vary the cooperative relation of the lever in eachtransmission to vary the effect of a given expansion of its respectivebellows on said rocker bar actuator, screw means to adjust the fulcrumfor each bellows actuated lever, and check rods to restrain the leverswith adjustable fulcrums from -lineal. movement.

3.-In' a. hydraulic scale, in combination, a load receiver, loadcounterbalancing means, a plurality of pairs of expansible members, eachpair comprising .a diaphragm and a bellows and being independentlyconnected by a duct, a body of liquid which fills and is confined withineach duct and its respective expansible members, the diaphragms disposedat the ends of the ducts being adapted yieldably to support said loadreceiver, a plurality of leverage transmissions, each independentlyresponsive to the expansion of same bellows at the other end of eachduct and each transmission including a lever, means jointly operable bysaid transmissions for transmitting force to said load counterbalancingmeans, shiftable connections between said levers and said transmittingmeans whereby the force transmitted by each lever may be independentlyadjusted, each of said bellows being rigidly connected to thecorresponding lever of said transmissions.

4. In a hydraulic scale, in combination, a load receiver, a movableweight indicator, a plurality of pairs of expansible members, each paircomprising a diaphragm and a bellows and being independently connectedby a duct, a body of liquid which fills and is confined within each ductand its respective expansible members, the diaphragm disposed at one endof each duct being adapted yieldably to support said load receiver, aplurality of leverage transmissions, each supporting the platform'or thebellows that independently responsive to the expansion of said bellowsat the other end of each duct and rigidly connected thereto, actuatingmeans jointly operable by said transmissions for actuating saidindicator, each of said leverage transmissions comprising a lever and asubstantially parallel cooperating arm of said actuating means fulcrumedat opposite ends and a connecting means slidable along said lever andarm to regulate the force transmitted to the indicator actuating means.

5. In a hydraulic scale, in combination, a scale platform, a pluralityof diaphragm elements supporting said platform, a load counterbalance, apivoted actuator therefor, a plurality of leverage transmissions whichjointly operate said pivoted actuator, a bellows connected to each ofsaid plurality of leverage transmissions for actuating said leveragetransmissions, there being an element in each leverage transmissionwhich is bodily shiftable to assume different operating positions inline with the leverage transmission pull to regulate its effect on theactuator, fiuid ducts each connecting a platform supporting diaphragmwith a corresponding bellows, and means to fill each pair of diaphragmsand bellows and their respective ducts with a confined liquid body, eachleverage transmission comprising a pair of substantially parallellevers, one attached to the pivoted actuator and the other having at itsend remote from the axis of said pivoted actuator an adjustable fulcrum.

6. In a hydraulic scale, in combination, a load receiver, a movableweight indicator, a plurality of pairs of expansible members, each paircomprising a diaphragm and a bellows independently connected to eachother by a duct, a body of liquid which fills and is confined withineach duct and its diaphragm and bellows, the diaphragms disposed at theends of the ducts beadapted yieldably to support said load receiver, anda multiple transmission for actuating said indicator, said transmissionbeing independently operable by each of said bellows and comprisingfulcrum and transmitter elements associated With means to eifectindependent relative adjustments between said elements whereby relativeleverage regulation is available to adjust the transmission, saidfulcrum elements comprising levers each having one of said bellowsrigidly connected intermediate its ends and independently adjustablepivots for said levers, said transmitter element comprising a commonpivoted member having lever arms cooperating with said levers interposedbetween said indicator and said levers.

'7. In a hydraulic scale, in combination, a. scale platform, a pluralityof diaphragm elements supporting said platform, a scale beam, a pivotedactuator therefor, a plurality of leverage transmissions which jointlyoperate said pivoted actuator, a bellows connected to each of saidplurality of leverage transmissions for actuating said leveragetransmissions, fluid ducts each connecting a platform diaphragm with acorresponding bellows, and means to fill each pair of diaphragms andbellows and their respective ducts with a confined liquid body, eachtransmission comprising a lever rigid with the pivoted actuator, a leveroperable by its respective actuating bellows and an adjustableconnection between the said levers in each transmission which comprisescoupling links and interposed knife edge bearing blocks.

8. In a hydraulic scale, in combination, a load receiver, loadcounterbalancing mechanism, a plurality of diaphragms supporting saidload re ceiver, a plurality of bellows, each of said diaphragms beingconnected by means of a duct to a separate one of said bellows, aplurality of levers, each of said bellows having an end seated upon aseparate one of said levers, means pivotally mounting each of saidlevers for movement about an axis substantially perpendicular to thecenter line of that one of said bellows seated on said lever wherebysaid lever and the end of said bellows seated thereon are constrained tomove only in a predetermined path, and means connecting each of saidlevers to said load counterbalancing mechanism.

9. In a hydraulic scale, in combination, a load receiver loadcounterbalancing mechanism, a plurality of diaphragms supporting saidload receiver, a plurality of bellows, each of said diaphragms beingconnected by means of a duct to a separate one of said bellows, aplurality of levers, each of said bellows having an end seated upon aseparate one of said levers, means pivotally mounting each of saidlevers for move-- ment about an axis substantially perpendicular to thecenter line of that one of said bellows seated on said lever wherebysaid lever and the end of said bellows seated thereon are constrained tomove only in a predetermined path, means connecting each of said leversto said load counterbalancing mechanism, and means for independentlyvarying the force transmitted by each of said levers to said loadcounterbalancing mechanism.

ROBERT S. BOHANNAN.

